Here is the breakage. This looks like a non-portable dependency on /dev/zero was introduced. expecting success of 4153.6 '--reject overrides --no-reject': rm -fr .git/rebase-apply && git reset --hard && git checkout first && rm -f file.rej && test_must_fail git am --no-reject side1.eml && test_path_is_dir .git/rebase-apply && test_path_is_missing file.rej && test_must_fail git am --retry --reject </dev/zero && test_path_is_dir .git/rebase-apply && test_path_is_file file.rej + rm -fr .git/rebase-apply + git reset --hard HEAD is now at 4f3810f side2 + git checkout first Warning: you are leaving 2 commits behind, not connected to any of your branches: 4f3810f side2 deca85c side1 If you want to keep them by creating a new branch, this may be a good time to do so with: git branch <new-branch-name> 4f3810f HEAD is now at 3aaf771 first + rm -f file.rej + test_must_fail git am --no-reject side1.eml Applying: side1 error: patch failed: file:1 error: file: patch does not apply Patch failed at 0001 side1 hint: Use 'git am --show-current-patch=diff' to see the failed patch hint: When you have resolved this problem, run "git am --continue". hint: If you prefer to skip this patch, run "git am --skip" instead. hint: To restore the original branch and stop patching, run "git am --abort". hint: Disable this message with "git config advice.mergeConflict false" + test_path_is_dir .git/rebase-apply + test_path_is_missing file.rej + test_must_fail git am --retry --reject + test_eval_inner_[6]: /dev/zero: cannot open error: last command exited with $?=1 not ok 6 - --reject overrides --no-reject # # rm -fr .git/rebase-apply && # git reset --hard && # git checkout first && # rm -f file.rej && # # test_must_fail git am --no-reject side1.eml && # test_path_is_dir .git/rebase-apply && # test_path_is_missing file.rej && # # test_must_fail git am --retry --reject </dev/zero && # test_path_is_dir .git/rebase-apply && # test_path_is_file file.rej # 1..6 -- Brief whoami: NonStop&UNIX developer since approximately UNIX(421664400) NonStop(211288444200000000) -- In real life, I talk too much.